Biomaterials based on calcium phosphate, and in particular based on hydroxyapatite Ca.sub.10 (PO.sub.4).sub.6 (OH).sub.2, are known for intraosteo or intradental filling. One can refer, for example, to the following publications concerning these apatitic biomaterials: "Jarche M. Kay J.F., Gumaer KI, Doremus R.H and Drobeck H.P Tissue, cellular and subcellular events at a bone-ceramic hydroxylapatite interface. J. Bioeng 1, 79, 1977"; "Ducheyne P and de Groot K, In vivo surface activity of a hydroxyapatite alveolar bone substitute, J. Biomed. Mater. Res. 14, 225, 1980"; "Klaas de Groot, Bioceramics of calcium phosphate, C.R.S. Press Inc., New York, 1983".
These biomaterials are known to have the following properties:
excellent biocompatibility (very limited risk of inflammatory rejection reactions),
very low solubility (low tendency to disappear in the medium over a course of several months after implantation),
osteoinduction quality (tendency to favor the reconstruction of bones).
These properties which make this material very appropriate for the production of bone or dental fillings, come from their chemical composition and their crystallographic structure, which are close to those of the mineral part of calcified tissue.
However, these known apatitic biomaterials are inactive with respect to pathogenic microorganisms susceptible of developing in the tissues. Thus, these biomaterials have essentially a mechanical role (bone filling and substitution) and have no antiseptic property: they are totally incapable of limiting the development of bacteria, funguses . . . which are present before intervention (caries, periodontal illnesses, . . . ) or which are the result thereof (aseptic imperfections, especially in the mouth, inflammations . . . ).
The present invention seeks to provide a new biomaterial having, as do the aforementioned known materials, an apatitic structure which confers excellent qualities of biocompatibility and osteoconduction or induction, but which has antiseptic properties making it capable of limiting the proliferation of microorganisms at the site of implantation.
The invention thus seeks to protect the graft in a local manner at the site of the implantation, while avoiding a use of antibiotics in general. It also seeks to assure this protection in a continuous manner over time, throughout the entire duration in which the material remains present at the implantation site.
Another object of the invention is to permit, after the case treated, adapting the scope of action of the biomaterial to the character of the microorganisms present or likely to develop at the site of implantation (in particular in order to fight in a specific manner against anaerobic microorganisms).